PHP OOP accessing global variable -

i have 2 php files. first library , other function problem if declare variable outside class error saying unidentified variable. need in advance.

lib.php

class test{     public function __construct()     {         $this->_link = mysql_connect('localhost','root','');         mysql_select_db('test_db', $this->_link);     }     public function query($sql)     {      } } 

function.php

include_once('lib.php'); $lib = new test();  function testfunction(){     $lib->query($sql); } 

the problem variable $db unidentified , don't want type $lib = new test() every function. in advance.

access variable inside every function using

function whatever($bar) {     global $lib;     $lib->foo($bar); 

or pass $lib parameter

function whatever($lib, $bar) {     $lib->foo($bar);